Wednesday, September 3, 2014

9223372036854775807 is a special number

The number 9223372036854775807 is a very special number in programming but why?

Take a look at this small program in .NET, I have declared a long integer and saved this number in it.


I will now increase this number by 1 and try to store it. I will try to store the 9223372036854775808 number Note the compile error I got in this code.



The reason it overflowed is because n is a signed long integer variable, which means it is a 64 bit number. This means it can hold up to 2^63 -1 only and the computer cannot store a number extra.


Make sure your calculations doesn't exceed this number in your future code!